Field of the Invention
The present invention relates generally to the fields of molecular biology and virology, and in particular, to methods for using recombinant adeno-associated virus (rAAV) compositions that express at least a first nucleic acid segment encoding at least a first therapeutic gene product, and particularly those products useful in the prevention, treatment, or amelioration of one or more symptoms of diseases, disorders, trauma, injury, or dysfunction of the mammalian eye. In particular embodiments, the invention provides compositions including rAAV vectors that express a biologically-functional guanylate cyclase peptide, polypeptide, or protein for use in one or more investigative, diagnostic and/or therapeutic regimens, including, for example, the treatment of one or more disorders or diseases of the mammalian eye, and in particular, for treating congenital retinal blindness including, retinal dystrophy such as Leber's congenital amaurosis, type 1 (LCA1), in humans. Also provided are methods for preparing rAAV vector-based guanylate cyclase medicaments for use in viral vector-based gene therapies, including, for example rAAV-LCA1 vectors for treating or ameliorating one or more symptoms of guanylate cyclase deficiency in humans.
Description of Related Art
Leber's congenital amaurosis (LCA) (formerly “amaurosis congenita of Leber”), first described as a congenital type of retinitis pigmentosa (RP) by German ophthalmologist Dr. Theodor Leber in 1869, is the earliest and most severe form of inherited retinopathy, and accounts for about 6% of all inherited retinal dystrophies. LCA is a group of degenerative diseases of the retina, and is the most common cause of congenital blindness in children. This autosomal recessive condition is usually recognized at birth or during the first months of life in an infant with total blindness or greatly impaired vision, normal fundus and extinguished electroretinogram (ERG) (see e.g., Perrault et al., 1996). Despite these functional deficits, LCA1 patients retain some rod and cone photoreceptors in both their macular and peripheral retina for years. Symptoms of the disease include retinal dysfunction, wobbly eye movement (nystagmus), impaired vision, slow pupil response, and ultimately, blindness.
Through genetic analyses, mutations in guanylate cyclase-1 (Gucy2d), assigned to the LCA1 locus, have been shown to account for 20% of all reported cases of LCA (see e.g., Milam et al., 2003; Perrault et al., 1996; Perrault et al., 2000). The number of patients affected by LCA1 is approximately twice that of patients affected by defects in the Retinal pigment epithelium-specific 65-kDa protein (RPE65) version of the disease (LCA2), which has garnered much attention in the gene therapy community in recent years.
It is estimated that 200,000 Americans have type 1 Leber's. Gucy2d encodes guanylate cyclase (retGC1) which is expressed in photoreceptor outer segment membranes (see e.g., Dizhoor et al., 1994; Liu et al., 1994), and plays a role in the recovery phase of phototransduction. Mutations which reduce or abolish activity of this enzyme are thought to create the biochemical equivalent of chronic light exposure in rod and cone photoreceptors. LCA is usually regarded as the consequence of either impaired development of photoreceptors or extremely early degeneration of cells that have developed normally. The LCA1 locus (GUCY2D) has been mapped to human chromosome 17p13.1 (LCA1) by homozygosity mapping.